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Show The estimated cost of desalting water, based on present and projected future technology, is shown in Figure H- 5. The chart shows that the cost varies with the size of the plant and the quality of the water to be desalted. 158 20 The Utah Desalting Study indicates that desalted water delivered into the Salt Lake City municipal system at an estimated cost of $ 75 to $ 100 per acre- foot would probably be competitive with water from other sources. Recent cost estimates for desalting plants and water collection and conveyance systems based on July 1971 prices indicate that water from this source would cost $ 150 to $ 200 per acre- foot, not including Bonneville Unit incurred costs. Geothermal Sources Natural underground reservoirs of steam and hot water are a subject of recent interest in the quest for new sources of energy and water. The aggregate installed capacity of geothermal powerplants throughout the world has already reached a million kilowatts. Geothermal reservoirs are heated by a large body of molten rock that has been pushed up near the earth's crust be geological forces. The water in fissures and porous rocks is heated to temperatures near 500° F. The water is under high pressure in liquid form at depths of around 3 to 6 miles. When the water escapes through a fissure it flashes off as steam. This steam carries liquid water with it to the surface. In most cases the water is brackish or slightly saline and therefore requires desalination for domestic use. Wells drilled to these depths can tap the thermal energy of the underground thermal reservoir. The primary purpose is to produce electrical power. In many cases the water produced from the condensation of the steam can also be used for some other purpose. The United States Geological Survey has classified two areas in Utah as known geothermal resource areas ( KGRA's). It is anticipated that these areas will be investigated by private or governmental agencies. Numerous areas elsewhere in the state have- been classified as prospective valuable geothermal areas ( PVGA's), and reconnaissance surveys are required to determine their potential. The two KRGA's are characterized by springs that issue from volcanic rocks or that are close to areas of quaternary or late tertiary volcanic rocks. The two springs are Abraham Springs ( Crater Springs), Juab County, 18 miles northwest 521 |
